Systems and methods for active noise cancellation for interior of autonomous vehicle

ABSTRACT

Various technologies described herein pertain to active noise cancellation in the interior of a vehicle. In exemplary embodiments, a microphone mounted on the vehicle outputs an audio signal indicative of noise emitted by a noise source. A computing system of the vehicle determines a position of the noise source based upon sensor signals output by sensors mounted on the vehicle. The computing system further determines a position of a passenger in the vehicle based upon a sensor mounted inside the vehicle. The computing system generates a complementary signal that is configured to attenuate the noise based upon the audio signal, the position of the noise source, and the position of the passenger. The complementary signal is then output by way of a speaker in the interior of the vehicle.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/224,203 filed on Dec. 18, 2018 and entitled “SYSTEMS AND METHODS FORACTIVE NOISE CANCELLATION FOR INTERIOR OF AUTONOMOUS VEHICLE,” theentirety of which is incorporated herein by reference.

BACKGROUND

An autonomous vehicle (AV) is a motorized vehicle that can operatewithout a human driver. An exemplary autonomous vehicle includes aplurality of sensor systems, such as but not limited to, a lidar sensorsystem, a camera sensor system, and a radar sensor system, amongstothers. The autonomous vehicle operates based upon sensor signals outputby the sensor systems.

Some vehicles include systems and components that are intended tomitigate various types of noise that result during operation of thevehicle. For instance, some vehicles include components that areintended to isolate the interior of the vehicle from the enginecompartment in order to reduce audible engine noise in the interior ofthe vehicle. Some vehicles also include dampening components that areintended to dampen noise-causing vibrations of various parts of thevehicle. Passive approaches to noise mitigation in vehicles generallystill allow significant noise in the interior of the vehicle, however,given the size, weight, and aesthetic constraints for noise mitigationcomponents.

Active noise cancellation now finds application in headphones.Conventionally, active noise cancellation headphones incorporate amicrophone, processing circuitry, and a speaker (ordinarily the samespeaker used to output whatever the listener is listening to). Themicrophone is positioned in close proximity to the listener's ear andreceives ambient noise from the listener's environment. The microphoneoutputs an audio signal indicative of the received noise. The processingcircuitry receives the audio signal output by the microphone andgenerates a phase-shifted signal that is 180° out of phase with theaudio signal. The phase-shifted signal is then output by the speaker,which is also positioned in close proximity to the listener's ear. Thisapproach may be suitable to attenuate ambient noise when there is amicrophone and a speaker positioned close to a listener's ear (e.g.,within three inches of the listener's ear), but this approach exhibitspoor performance when the microphone used to detect the noise and/or thespeaker used to output the phase-shifted signal are farther away fromthe listener.

SUMMARY

The following is a brief summary of subject matter that is described ingreater detail herein. This summary is not intended to be limiting as tothe scope of the claims.

Described herein are various technologies that pertain to active noisecancellation within an interior of a vehicle. With more particularity,technologies are described herein for attenuating noise heard by apassenger in a passenger cabin of an AV that originates from noisesources outside the vehicle. In an exemplary embodiment, a microphonemounted on the vehicle receives a sound from a noise source external tothe vehicle (e.g., noise from a construction zone, a siren of anemergency-response vehicle, a horn of another vehicle, or substantiallyany other source of noise in a driving environment of the AV).Responsive to the sound impinging on the microphone, the microphoneoutputs an audio signal (e.g., an electrical or optical signal) that isrepresentative of the sound. The audio signal is received by a digitalsignal processing module (DSP). Further, a sensor in the passenger cabinof the AV outputs data indicative of a position of a head of a passengerin the AV. The DSP receives the data and outputs a complementary signalbased upon the audio signal and the data indicative of the position ofthe head of the passenger. As used herein, a complementary signal isconfigured such that when the complementary signal is output to aspeaker inside the passenger cabin, the speaker generates a sound thatcauses the sound of the noise source to be attenuated at the position ofthe head of the passenger.

In another exemplary embodiment, the DSP generates the complementarysignal based upon the audio signal output by the microphone and alocation of the noise source in the driving environment of the AV. Inthe embodiment, a sensor mounted on the AV outputs a sensor signal thatis indicative of objects in the driving environment. By way of example,the sensor can be a lidar sensor that outputs a signal indicative ofpositions of objects in the driving environment. In another example, thesensor can be a vision sensor (e.g., a camera) that outputs images ofthe driving environment. A computing system included on the AV canidentify a location of the noise source in the driving environment basedupon the output of the sensor. The DSP generates the complementarysignal based upon the audio signal output by the microphone and thelocation of the noise source identified by the computing system, whichmay include or be in communication with the DSP. The complementarysignal can then be output to one or more speakers in the passenger cabinof the AV.

The above-described technologies present various advantages overconventional noise mitigation technologies. First, the above-describedtechnologies provide greater noise mitigation than passivenoise-dampening approaches alone. Second, the active noise cancellationtechniques described herein provide greater attenuation of noise thanconventional active noise cancellation techniques when thenoise-detecting microphone and the speaker that outputs an interferingsignal are not in close proximity to the passenger (e.g., greater thansix inches from the passenger's head).

The above summary presents a simplified summary in order to provide abasic understanding of some aspects of the systems and/or methodsdiscussed herein. This summary is not an extensive overview of thesystems and/or methods discussed herein. It is not intended to identifykey/critical elements or to delineate the scope of such systems and/ormethods. Its sole purpose is to present some concepts in a simplifiedform as a prelude to the more detailed description that is presentedlater.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a functional block diagram of an exemplary autonomousvehicle.

FIG. 2 illustrates a functional block diagram of an exemplary autonomousvehicle.

FIG. 3 illustrates an exemplary driving environment of an autonomousvehicle that includes various sources of noise.

FIG. 4 illustrates a top-down cutaway view of a passenger cabin of avehicle.

FIG. 5 illustrates exemplary positions of an array of microphones aboutthe exterior of a vehicle.

FIG. 6 is a flow diagram that illustrates an exemplary methodologyperformed by a vehicle in connection with providing active noisecancellation based upon a position of a head of a passenger of thevehicle.

FIG. 7 is a flow diagram that illustrates an exemplary methodologyperformed by a vehicle in connection with providing active noisecancellation based upon a location of a noise source in a drivingenvironment of the vehicle.

FIG. 8 illustrates an exemplary computing device.

DETAILED DESCRIPTION

Various technologies pertaining to active noise cancellation in aninterior of an autonomous vehicle are now described with reference tothe drawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of one or more aspects. It may be evident,however, that such aspect(s) may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to facilitate describing one or moreaspects. Further, it is to be understood that functionality that isdescribed as being carried out by certain system components may beperformed by multiple components. Similarly, for instance, a componentmay be configured to perform functionality that is described as beingcarried out by multiple components.

Moreover, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” That is, unless specified otherwise, or clearfrom the context, the phrase “X employs A or B” is intended to mean anyof the natural inclusive permutations. That is, the phrase “X employs Aor B” is satisfied by any of the following instances: X employs A; Xemploys B; or X employs both A and B. In addition, the articles “a” and“an” as used in this application and the appended claims shouldgenerally be construed to mean “one or more” unless specified otherwiseor clear from the context to be directed to a singular form.

As used herein, the terms “component” and “system” are intended toencompass computer-readable data storage that is configured withcomputer-executable instructions that cause certain functionality to beperformed when executed by a processor. The computer-executableinstructions may include a routine, a function, or the like. It is alsoto be understood that a component or system may be localized on a singledevice or distributed across several devices. Further, as used herein,the term “exemplary” is intended to mean “serving as an illustration orexample of something.”

Referring now to the drawings, FIG. 1 illustrates an autonomous vehicle100 in an exemplary driving environment 101. The autonomous vehicle 100can navigate about roadways without human conduction based upon sensorsignals outputted by sensor systems of the autonomous vehicle 100. Theautonomous vehicle 100 includes a plurality of sensor systems, namely, asensor system 1 102, . . . , and a sensor system N 104, where N can besubstantially any integer greater than 1 (collectively referred toherein as sensor systems 102-104). The sensor systems 102-104 are ofdifferent types and are arranged about the autonomous vehicle 100. Forexample, the sensor system 1 102 may be a lidar sensor system and thesensor system N 104 may be a directional microphone array. Otherexemplary sensor systems included in the sensor systems 102-104 caninclude radar sensor systems, cameras, GPS sensor systems, sonar sensorsystems, infrared sensor systems, and the like.

The autonomous vehicle 100 further includes several mechanical systemsthat are used to effectuate appropriate motion of the autonomous vehicle100. For instance, the mechanical systems can include, but are notlimited to, a vehicle propulsion system 106, a braking system 108, and asteering system 110. The vehicle propulsion system 106 may be anelectric motor, an internal combustion engine, or a combination thereof.The braking system 108 can include an engine brake, brake pads,actuators, and/or any other suitable componentry that is configured toassist in decelerating the autonomous vehicle 100. The steering system110 includes suitable componentry that is configured to control thedirection of movement of the autonomous vehicle 100.

The autonomous vehicle 100 additionally includes a computing system 112that is in communication with the sensor systems 102-104, the vehiclepropulsion system 106, the braking system 108, and the steering system110. The computing system 112 includes a processor 114 and memory 116.The memory 116 includes computer-executable instructions that areexecuted by the processor 114. Pursuant to various examples, theprocessor 114 can be or include a graphics processing unit (GPU), aplurality of GPUs, a central processing unit (CPU), a plurality of CPUs,an application-specific integrated circuit (ASIC), a microcontroller, aprogrammable logic controller (PLC), a field programmable gate array(FPGA), or the like.

The memory 116 of the computing system 112 also includes a perceptionsystem 118. Generally, the perception system 118 is configured to trackobjects in a driving environment of the AV 100 based upon sensor signalsoutput by the sensor systems 102-104. In various embodiments, theperception system 118 receives the sensor signals output by the sensorsystems 102-104 and identifies the presence of objects in the drivingenvironment such as other vehicles, pedestrians, cyclists, etc. Theperception system 118 can be configured to classify the identifiedobjects according to one or more of various types such as car, truck,pedestrian, cyclist, static objects (e.g., utility poles, garbage cans,trees, etc.), unknown, etc. Still further, the perception system 118 canbe configured to output locations of objects in the driving environment.Accuracy and precision of the locations output by the perception system118 can vary based upon the type of sensor systems 102-104 included onthe AV 100. By way of example, where one of the sensor systems 102-104is a lidar sensor, the perception system 118 may be able to identifylocations of objects in the driving environment that are accurate towithin 5 centimeters or less. In another example, where the perceptionsystem 118 identifies locations of objects based upon output of amicrophone array (e.g., using time-difference-of-arrival techniques),the identified locations may be less accurate. The memory 116 of thecomputing system 112 further includes a control system 126. The controlsystem 126 is configured to control at least one of the mechanicalsystems of the autonomous vehicle 100 (e.g., at least one of the vehiclepropulsion system 106, the braking system 108, and/or the steeringsystem 110). Generally, the control system 126 controls operation of theAV 100 based upon data output by the perception system 118 that pertainsto the driving environment of the AV 100.

During operation of the AV 100 in a driving environment, there may bevarious noise sources that emit sounds that are audible within aninterior of the AV 100 (e.g., in a passenger cabin of the AV 100). Forinstance, as the AV 100 operates, a noise source 120 emits a sound 122that is potentially audible to a passenger 124. The sound 122 may bedistracting or unpleasant to the passenger 124, who may be carrying on aconversation or attempting to concentrate on other things. The AV 100 isconfigured to provide active cancellation of noise within a passengercabin of the AV 100 such that the sound 122 emitted by the noise source120 is attenuated inside the passenger cabin relative to a level of thesound 122 absent the active noise cancellation.

In connection with providing active noise cancellation within aninterior of the AV 100, the AV further includes a DSP 126, at least onemicrophone 128, and at least one speaker 130. Still further, the memory116 includes a noise cancellation system 132 that is in communicationwith the DSP 126. The microphone 128 receives the sound 122 emitted bythe noise source 120. Stated differently, the sound wave 122 emitted bythe noise source 120 impinges on the microphone 128. The microphone 128outputs an audio signal that is representative of the sound 122 to theDSP 126. The DSP 126 generates a complementary signal based upon theaudio signal output by the microphone 128. The DSP 126 outputs thecomplementary signal to the speaker 130, whereupon the speaker 130 emitsa sound 134 toward the passenger 124. The complementary signal isconfigured such that the sound 134 emitted by the speaker destructivelyinterferes with the sound 122 emitted by the noise source 120 at theposition of the passenger 124 in the AV 100, thereby attenuating thesound 122 in the perception of the passenger 124.

In exemplary embodiments, the DSP 126 generates the complementary signalbased upon the audio signal output by the microphone 128 using varioussignal processing techniques. For example, responsive to receipt of theaudio signal, the DSP 126 can perform a fast Fourier transform (FFT)over the audio signal to generate a frequency-domain representation ofthe audio signal. In embodiments wherein the microphone outputs ananalog audio signal to the DSP 126, the DSP 126 can performanalog-to-digital conversion of the audio signal to generate a digitalrepresentation of the audio signal prior to executing the FFT. From thefrequency-domain representation of the audio signal, the DSP 126 candetermine relative amplitudes of various spectral components of theaudio signal. The DSP 126 can then generate the complementary signalsuch that when the complementary signal and the audio signal interfere,the resulting interference combination exhibits attenuation in one ormore of the spectral components of the audio signal.

In various exemplary embodiments set forth in greater detail below, theDSP 126 generates the complementary signal based further upon datapertaining to a position of the head of the passenger 124 in the AV 100and/or an identified location of the noise source 120. In an example,the perception system 118 can be configured to identify, based uponsensor signals output by the sensor systems 102-104, a location of ahead of the passenger 124 and/or a position of the noise source 102 inthe driving environment 101. The noise cancellation system 132 canoutput either or both of the identified positions to the DSP 126. As setforth in greater detail below, the DSP 126 can generate thecomplementary signal based upon sound propagation models that take intoaccount the position of the head of the passenger 124. and/or thelocation of the noise source 120.

It is further to be appreciated that the AV 100 can also include variouspassive noise cancellation elements such as insulation in the doors,side panels, or other components of the AV 100. Furthermore, passivenoise cancellation elements included in the AV 100 can be configured todampen noise to a greater extent than would be allowable for a vehiclerequiring human conduction. By way of example, a vehicle operated byhuman conduction would be required to allow the sounds of sirens or carhorns to be heard within the passenger cabin of the vehicle to ensuresafe operation by the human driver. In contrast, the AV 100 can includepassive noise cancellation elements that generally do not allow suchsounds to be heard, or that generally dampen such sounds to a greaterextent than allowable by various laws, rules, and regulations pertainingto human-operated vehicles.

With reference now to FIG. 2, an exemplary AV 200 is illustrated inaccordance with various embodiments of the AV 100. The AV 200 includesthe computing system 112, the DSP 126, and the microphone 128. While notshown, it is to be appreciated that the AV 200 further includes thesensor systems 102-104 and the mechanical systems (e.g., systems106-110) as described above with respect to the AV 100. In accordancewith various embodiments, the AV 200 further includes an interior sensorsystem 202, an exterior sensor system 204, and a plurality of M speakers206-208, where M is an integer greater than zero. The interior sensorsystem 202 is configured to output a sensor signal that is indicative ofpositions of objects in a passenger cabin of the AV 200. The exteriorsensor system 204 is generally configured to output a sensor signal thatis indicative of positions of objects outside the AV 200 in a drivingenvironment of the AV 200, such as other vehicles in the drivingenvironment.

In the exemplary AV 200, the DSP 126 includes a noise propagation model210 that models the propagation of sounds through the drivingenvironment of the AV 200. In the exemplary AV 200, the DSP 126 furtherincludes a beamforming component 212 that generates a respective signalfor each of the plurality of speakers 206-208 based upon an audio signalrepresentative of sound desirably output to a position in the passengercabin of the AV 200. The DSP 126 further includes an interiorpropagation model 214 that models the propagation of sounds inside apassenger cabin of the AV 200. The interior propagation model 214 caninclude a model indicative of propagation of sound from each of thespeakers 206-208 to various positions in the passenger cabin of the AV200.

Details pertaining to exemplary operations of the AV 200 in connectionwith performing active noise cancellation within a passenger cabin ofthe AV 200 are now set forth with respect to FIGS. 2-5. Referring now toFIG. 3, an exemplary driving environment 300 is illustrated wherein theAV 200 approaches a four-way stop intersection 302. The drivingenvironment 300 further includes an emergency vehicle 304 and aconstruction crew 306. The emergency vehicle 304 and the constructioncrew 306 can be considered noise sources in the driving environment 300,and they emit respective sounds 308, 310. The sounds 308, 310 emitted bythe emergency vehicle 304 and the construction crew 306 are eventuallyreceived at the AV 200, where they impinge on the microphone 128.

Referring again to FIG. 2, responsive to a sound impinging on themicrophone 128, the microphone outputs an audio signal (e.g., anelectrical signal or an optical signal) that is indicative of the soundthat impinges on the microphone 128. The DSP 126 receives the audiosignal, the audio signal being indicative of noise received at the AV200. As noted above, the DSP 126 generates a complementary signal basedon the audio signal. The complementary signal is a signal that isconfigured such that when the complementary signal is output by way of aspeaker, the sound emitted by the speaker destructively interferes withthe sound of which the audio signal output by the microphone 128 isrepresentative (e.g., a sound emitted by a noise source). Thedestructive interference between the sound emitted by the speaker andthe sound emitted from the noise source causes attenuation of the soundemitted from the noise source, thereby resulting in cancellation of thenoise.

The DSP 126 can be further configured to output the complementary signalbased upon a position of a head of a passenger in a passenger cabin ofthe AV 200. In an exemplary embodiment, the perception system 118receives a sensor signal from the interior sensor system 202. The sensorsignal output by the interior sensor system 202 is indicative of objectsin an interior of the AV 200. The perception system 118 outputs aposition of a head of passenger based upon the sensor signal output bythe interior sensor system 202. In an exemplary embodiment, the interiorsensor can be an imaging system such as a camera, or a depth camera.Referring now to FIG. 4, a top-down cutaway view 400 of an exemplaryvehicle 402 is illustrated, wherein a passenger cabin 404 of the vehicle402 is shown. Several passengers 406-410 are shown positioned in thepassenger cabin 404. A camera 412 is positioned facing the passengercabin 404 such that the camera 412 captures images of the passengers406-410. The camera 412 can be configured to output a stream of imagesof the passenger cabin 404. In exemplary embodiments, the camera 412 canbe configured to output color images of the passenger cabin 404, depthimages of the passenger cabin 404 wherein pixel values of a depth imageare indicative of distance from the camera 412, or substantially anyother images that are suitable for identifying positions of passengers'heads. A perception system of the AV 402 can receive the images andidentify positions of the heads of the passengers 406-410 based on theimages. By way of example, the perception system of the AV 402 canoutput, based on the images, a three-dimensional position of a head ofone of the passengers 406-410 within the passenger cabin 404.

Referring again to FIG. 2, the DSP 126 receives a position of a head ofa passenger in a passenger cabin of the AV 200 from the perceptionsystem 118. The DSP 126 generates a complementary signal based upon theposition of the head of the passenger and an audio signal output by themicrophone 128, the audio signal indicative of a sound received fromnoise sources outside the AV 200. The DSP 126 can generate thecomplementary signal based upon the interior propagation model 214.

The interior propagation model 214 can be calibrated based upon signalsoutput by microphones positioned in the passenger cabin of the vehicle200. In an exemplary embodiment, the interior sensor system 202 includesa plurality of microphones that are positioned in the passenger cabin ofthe vehicle 200. Known calibration signals can be output by way of thespeakers 206-208. Each of the microphones outputs a respective audiosignal that is indicative of the calibration sound received at themicrophone. Based upon amplitude, phase, and frequency of the audiosignals, the noise cancellation system 132 can identify a respectivetransfer function for each of the speakers 206-208 that indicates achange to the sound output by the speaker to each of a plurality ofpoints in the passenger cabin of the vehicle. The interior propagationmodel 214 includes these transfer functions, and allows a resultantsound that is delivered to a point in the passenger cabin to beidentified based on the transfer function and the sound originallyoutput by a speaker in the speakers 206-208.

In an exemplary embodiment, the DSP 126 can model propagation of theexternal noise through the passenger cabin to the identified position ofthe head of the passenger based upon the interior propagation model 214to generate a target complementary signal. In exemplary embodiments, theinterior propagation model 214 is indicative of phase and amplitudechanges of sounds as they travel through the passenger cabin of the AV200. The DSP 126 generates a representation of the noise at the positionof the head of the passenger based on the interior propagation model214. In an example, the DSP 126 generates the representation of thenoise at the position of the head of the passenger by imparting a phaseand amplitude adjustment to the audio signal output by the microphone128, the phase and amplitude adjustments based on the interiorpropagation model 214. The DSP 126 then generates a target complementarysignal that is representative of sound desirably delivered to theposition of the head of the passenger. The DSP 126 generates the targetcomplementary signal such that the target complementary signal and therepresentation of the noise at the position of the head of the passengercompletely or partially destructively interfere with one another,resulting in attenuation of the noise.

The DSP 126 generates a complementary signal to be output to one or moreof the speakers 206-208 based on the target complementary signal and theinterior propagation model 214. By way of example, the DSP 126 cangenerate the complementary signal such that the interior propagationmodel 214 indicates that when the complementary signal is output assound by one or more of the speakers 206-208, it is approximately equalto the target complementary signal at the position of the head of thepassenger. The complementary signal can then be output by one or more ofthe speakers 206-208, whereupon sound emitted by the speakers 206-208based upon the complementary signal interferes with the noise at theposition of the head of the passenger in order to attenuate the noise.

In various embodiments, the DSP 126 can generate a plurality of partialcomplementary signals by way of the beamforming component 212, whereineach of the partial complementary signals is configured to be output bya different speaker in the speakers 206-208. The beamforming component212 generates the partial complementary signals such that when thosesignals are output by way of the speakers 206-208 as sounds, thosesounds interfere at the position of the head of the passenger to resultin a desired signal being heard by the passenger. The beamformingcomponent 212 is configured to compute the partial complementary signalsbased upon the position of the head of the passenger and a targetcomplementary signal that is desirably delivered to the position of thehead of the passenger as a sound wave. The beamforming component 212generates the partial complementary signals using various beamformingalgorithms according to which the phase and/or amplitude of each of thepartial complementary signals is adjusted in order to yield a desiredwaveform at a target location (e.g., the position of the head of thepassenger).

When the partial complementary signals are output by way of the speakers206-208, the sounds emitted by the speakers interfere at the identifiedposition of the head of the passenger to yield a sound wave that issubstantially similar to the target complementary signal. For example,and referring again to FIG. 4, a plurality of speakers 414-424 arepositioned about the passenger cabin 404. A different partialcomplementary signal can be output by way of each of the speakers414-424 such that each of the speakers 414-424 emits a different sound.When the sounds emitted by the speakers 414-424 interfere at a locationin the passenger cabin 414 (e.g., a position of the head of one of thepassengers 406-410), the sounds constructively interfere with each otherto yield a sound substantially similar to the target complementarysignal. These sounds destructively interfere with noise at the location,thereby resulting in attenuation of the noise.

Use of the beamforming component 212 as described herein allows agreater range of sounds to be delivered to a more precise region aroundthe position of the head of the passenger. In turn, this allows forgreater attenuation for a greater variety of noise at the position ofthe head of the passenger than would be possible using a single speakerin connection with the technologies described herein, or that would bepossible with conventional active noise cancellation techniques.

The DSP 126 can be further configured to output the complementary signalbased upon a location of a noise source in the driving environment ofthe AV 200. By determining the location of the noise source, the AV 200can accurately determine a phase value of the noise at the microphone128 and a phase value of the noise when it reaches a particular locationin the passenger cabin of the AV 200 (e.g., a position of a passenger'shead). The DSP 126 can then generate the complementary signal based uponthe phase value of the noise at the location in the passenger cabin,such that a phase of the complementary signal is aligned to causegreater attenuation of the noise than can ordinarily be achieved usingconventional active noise cancelling systems.

In exemplary embodiments, the exterior sensor system 204 is anoutward-facing sensor system that outputs a sensor signal that isindicative of one or more objects in a driving environment of the AV200. As noted above, the exterior sensor system 204 can be one of aplurality of sensor systems (e.g., sensor systems 102-104) thatcontinuously output data during operation of the AV 200 in connectionwith controlling various functions of the AV 200. For example, theexterior sensor system 204 can be any or several of a lidar sensor, aradar sensor, a camera, a directional microphone array, etc. Theperception system 118 computes locations for a plurality of objects inthe driving environment of the AV 200 based upon sensor signals outputby the exterior sensor system 204.

The noise cancellation system 132 can be configured to identify which ofa plurality of objects identified by the perception system 118 in thedriving environment of the AV 200 is likely to be the source of a noisereceived at the microphone 128. In an exemplary embodiment, the noisecancellation system 132 receives data indicative of the audio signaloutput by the microphone 128. For instance, the noise cancellationsystem 132 can receive a frequency domain representation of the audiosignal from the DSP 126, where the frequency-domain representation isindicative of amplitudes of various spectral components of the audiosignal. The noise cancellation system 132 can identify which of aplurality of objects in the driving environment of the AV 200 is a noisesource based upon the data indicative of the audio signal output andother data pertaining to the driving environment that are output by theperception system 118.

By way of example, and not limitation, when the audio signal is stronglytonal, the noise cancellation system 132 can determine that a noisesource is a vehicle in the driving environment, on the assumption thatthe tonal noise is due to a vehicle siren or horn. In another example,the noise cancellation system 132 can determine that the noise source isa particular type of object in the driving environment based on acomparison of the audio signal to a signature of a certain type ofobject. For instance, in the driving environment 300 illustrated in FIG.3, the noise cancellation system 132 of the AV 200 can compare the sound310 received at the microphone 128 as represented by the audio signaloutput by the microphone 128 to a signature for construction site noise.Responsive to determining that the audio signal is substantially similarto the signature for the construction site noise, the noise cancellationsystem 132 of the AV 200 can determine which, if any, objects in thedriving environment 300 are likely part of a construction site based ondata output by the perception system 118. If, for example, theperception system 118 indicates that the construction crew 306 is likelyassociated with a construction site (e.g., the perception system 118identifies that the construction crew 306 includes a group of peoplewearing reflective vests), the noise cancellation system 132 candetermine that the construction crew 306 is the source of the noise.

In other embodiments, the noise cancellation system 132 can identify alocation of a noise source based upon output of a microphone array. Inan exemplary embodiment, the exterior sensor system 204 comprises alidar sensor system and a microphone array that comprises a plurality ofmicrophones. By way of example, and referring briefly to FIG. 5, anexemplary vehicle 500 is shown that includes a plurality of microphones502-516 arranged about the vehicle 500. Depending on a direction anddistance from which noise originates, the microphones 502-516 willreceive noise from a noise source in the driving environment atdifferent times. Referring again to FIG. 2, if the exterior sensorsystem 204 of the AV 200 includes a microphone array, the noisecancellation system 132 can use TDOA, angle-of-arrival (AOA), and/ordirection finding techniques to determine a coarse position solution forthe noise source. Depending on factors such as a number of microphonesin the exterior sensor system 204, sampling rates of the microphones(e.g., sampling rate of an analog-to-digital converter that digitizesthe outputs of the microphones), bandwidth of the received noise, etc.,the coarse position solution can indicate a position that is accurate towithin ten meters, within 50 meters, or within 100 meters. In someembodiments, the coarse position solution of the noise source may beaccurate enough for computation of phase values of the noise from thenoise source.

In other embodiments, the coarse position solution can be used todistinguish between more accurate position solutions for objects in thedriving environment. By way of example, and referring again to FIG. 3, acoarse position solution that indicates that the sound 308 originatesfrom the left side of the AV 200 can be used by the noise cancellationsystem 132 to determine that the emergency vehicle 304 is the source ofthe sound 308 rather than the construction crew 306. The noisecancellation system 132 can then determine that a position of theemergency vehicle 304 identified by the perception system 118 is theposition of the noise source, which position may be identified by theperception system 118 based on more accurate positioning data such asdata from a lidar sensor.

Responsive to the noise cancellation system 132 determining a locationof the noise source, the noise cancellation system 132 outputs thelocation of the noise source to the DSP 126. The DSP 126 then generatesthe complementary signal for the noise based upon the location of thenoise source and the audio signal output by the microphone 128, which isrepresentative of the noise as received at the microphone 128. In anexemplary embodiment, the DSP 126 determines a phase of the noise basedupon the audio signal and the noise propagation model 210. The DSP 126back-propagates the noise waveform, represented by the audio signal,from the location of the microphone 128 to the location of the noisesource based on the noise propagation model 210, which is indicative ofchanges to the noise waveform as it travels in space. In variousembodiments, the noise propagation model 210 incorporates datapertaining to conditions that affect propagation of sound in the drivingenvironment such as temperature, humidity, altitude, etc. The DSP 126recovers a representation of the original noise waveform output by thenoise source from the back-propagation.

The DSP 126 then forward-propagates the original noise waveform from thelocation of the noise source to a desired location for noisecancellation in the passenger cabin of the AV 200 (e.g., a position of apassenger's head) based upon the noise propagation model 210. Inaddition to incorporating data pertaining to conditions in the drivingenvironment, the noise propagation model 210 can include a transferfunction that represents modification of the noise waveform from theexterior of the vehicle to the interior of the vehicle. The DSP 126thereby generates an expected noise signal that is expected to be heardby a passenger at the location of desired noise cancellation, includinga precise estimate of phase of the expected noise signal. The DSP 126then generates a complementary signal that is configured to attenuatethe expected noise signal at the desired location in the passengercabin. In an exemplary embodiment, the DSP 126 generates a targetcomplementary signal based upon amplitudes of frequency components ofthe expected noise signal and the phase of the expected noise signalsuch that the target complementary signal and the expected noise signalcompletely destructively interfere. The DSP 126 can then output acomplementary signal or partial complementary signals (e.g., asdescribed above with respect to the beamforming component 212) to thespeakers 206-208, where the complementary or partial complementarysignals are configured to yield the target complementary signal at thedesired location when output by way of the speakers 206-208.

The systems set forth with respect to the AV 200 are able to attenuatenoise in the passenger cabin of the AV 200 to a greater extent thanpossible with systems that do not take into account the location of thenoise source, or the position of the head of a passenger in the vehicle.

While the above-described aspects have been set forth with respect toautonomous vehicles, it is to be understood that the active noisecancellation technologies described herein are also suitable for use invehicles that are operated by a human driver. Furthermore, the activenoise cancellation technologies set forth herein can be used inconjunction with various other passive noise mitigation componentry.Still further, it is to be understood that various actions describedherein as being performed by a DSP can be performed by a computingsystem or vice versa. By way of example, computations pertaining togenerating a complementary signal that are described herein as beingperformed by the DSP 126 can be performed by the processor 114 inconnection with executing instructions of the noise cancellation system132.

FIGS. 6 and 7 illustrate exemplary methodologies relating to activenoise cancellation for the interior of a vehicle. While themethodologies are shown and described as being a series of acts that areperformed in a sequence, it is to be understood and appreciated that themethodologies are not limited by the order of the sequence. For example,some acts can occur in a different order than what is described herein.In addition, an act can occur concurrently with another act. Further, insome instances, not all acts may be required to implement a methodologydescribed herein.

Moreover, the acts described herein may be computer-executableinstructions that can be implemented by one or more processors and/orstored on a computer-readable medium or media. The computer-executableinstructions can include a routine, a sub-routine, programs, a thread ofexecution, and/or the like. Still further, results of acts of themethodologies can be stored in a computer-readable medium, displayed ona display device, and/or the like.

With reference to FIG. 6, a methodology 600 for performing active noisecancellation in a vehicle interior based upon a position of a head of apassenger in the vehicle is illustrated. The methodology 600 begins at602, and at 604, an audio signal is received from a microphone, theaudio signal being indicative of noise emitted by a noise source in adriving environment of the vehicle. At 606 a position of a head of apassenger of the vehicle in the interior of the vehicle is identified.In an exemplary embodiment, the position of the head of the passenger isidentified based upon output of a sensor in the interior of the vehicle.At 608 a complementary signal is computed based upon the position of thehead identified at 606 and the audio signal received at 604. Thecomplementary signal is configured such that when the complementarysignal is output by way of a speaker, the complementary signalinterferes with the noise at the position of the head of the passenger,thereby attenuating the noise. The complementary signal is output to aspeaker in the interior of the vehicle at 610, whereupon the methodology600 completes 612.

With reference now to FIG. 7, a methodology 700 for performing activenoise cancellation in a vehicle interior based upon a location of anoise source in the driving environment is illustrated. The methodology700 begins at 702, and at 704 an audio signal is received from amicrophone, the audio signal indicative of a sound emitted by a noisesource in a driving environment of a vehicle. At 706, a location of thenoise source is determined. In an exemplary embodiment, the location ofthe noise source is determined based upon output of a sensor thatoutputs data indicative of objects in the driving environment (e.g., aradar sensor, a lidar sensor, a camera, a microphone array, etc.). Acomplementary signal is computed at 708 based upon the location of thenoise source and the audio signal received at 704. The complementarysignal is configured such that when the complementary signal is outputby a speaker in the interior of the vehicle, the speaker emits a soundthat causes the noise to be attenuated in the interior of the vehicle.At 710 the complementary signal is output to a speaker in the interiorof the vehicle, whereupon the methodology 700 completes 712.

Referring now to FIG. 8, a high-level illustration of an exemplarycomputing device 800 that can be used in accordance with the systems andmethodologies disclosed herein is illustrated. For instance, thecomputing device 800 may be or include the computing system 112. Thecomputing device 800 includes at least one processor 802 that executesinstructions that are stored in a memory 804. The instructions may be,for instance, instructions for implementing functionality described asbeing carried out by one or more systems discussed above or instructionsfor implementing one or more of the methods described above. Theprocessor 802 may be a GPU, a plurality of GPUs, a CPU, a plurality ofCPUs, a multi-core processor, etc. The processor 802 may access thememory 804 by way of a system bus 806. In addition to storing executableinstructions, the memory 804 may also store audio signal data, sensordata, calibration data, propagation models, computer-implemented machinelearning models, and so forth.

The computing device 800 additionally includes a data store 808 that isaccessible by the processor 802 by way of the system bus 806. The datastore 808 may include executable instructions, audio signal data, sensordata, calibration data, propagation models, computer-implemented machinelearning models, etc. The computing device 800 also includes an inputinterface 810 that allows external devices to communicate with thecomputing device 800. For instance, the input interface 810 may be usedto receive instructions from an external computer device, etc. Thecomputing device 800 also includes an output interface 812 thatinterfaces the computing device 800 with one or more external devices.For example, the computing device 800 may transmit control signals tothe vehicle propulsion system 106, the braking system 108, and/or thesteering system 110 by way of the output interface 812.

Additionally, while illustrated as a single system, it is to beunderstood that the computing device 800 may be a distributed system.Thus, for instance, several devices may be in communication by way of anetwork connection and may collectively perform tasks described as beingperformed by the computing device 800.

Various functions described herein can be implemented in hardware,software, or any combination thereof. If implemented in software, thefunctions can be stored on or transmitted over as one or moreinstructions or code on a computer-readable medium. Computer-readablemedia includes computer-readable storage media. A computer-readablestorage media can be any available storage media that can be accessed bya computer. By way of example, and not limitation, suchcomputer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium that can be used to store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Disk and disc, as used herein, includecompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk, and blu-ray disc (BD), where disks usually reproducedata magnetically and discs usually reproduce data optically withlasers. Further, a propagated signal is not included within the scope ofcomputer-readable storage media. Computer-readable media also includescommunication media including any medium that facilitates transfer of acomputer program from one place to another. A connection, for instance,can be a communication medium. For example, if the software istransmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio and microwave are includedin the definition of communication medium. Combinations of the aboveshould also be included within the scope of computer-readable media.

Alternatively, or in addition, the functionality described herein can beperformed, at least in part, by one or more hardware logic components.For example, and without limitation, illustrative types of hardwarelogic components that can be used include Field-programmable Gate Arrays(FPGAs), Application-specific Integrated Circuits (ASICs),Application-specific Standard Products (ASSPs), System-on-a-chip systems(SOCs), Complex Programmable Logic Devices (CPLDs), etc.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable modification and alteration of the above devices ormethodologies for purposes of describing the aforementioned aspects, butone of ordinary skill in the art can recognize that many furthermodifications and permutations of various aspects are possible.Accordingly, the described aspects are intended to embrace all suchalterations, modifications, and variations that fall within the scope ofthe appended claims. Furthermore, to the extent that the term “includes”is used in either the details description or the claims, such term isintended to be inclusive in a manner similar to the term “comprising” as“comprising” is interpreted when employed as a transitional word in aclaim.

What is claimed is:
 1. A vehicle comprising: a speaker positioned in aninterior of the vehicle; a microphone that receives a first sound thatis incident on the microphone, the first sound emitted by a noise sourcein a driving environment of the vehicle, wherein the microphone outputsan audio signal that is indicative of the first sound responsive to thefirst sound being incident on the microphone; a sensor system configuredto output data indicative of positions of objects in the drivingenvironment; and a computing system configured to perform the followingacts: identifying, based upon output of the sensor system, a position ofthe noise source in the driving environment; computing a complementarysignal based upon the position of the noise source and the audio signal;and outputting the complementary signal to the speaker, wherein thecomplementary signal is configured to cause the speaker to emit a secondsound that causes the first sound to be attenuated in an interior of thevehicle.
 2. The vehicle of claim 1, wherein computing the complementarysignal based upon the position of the noise source and the audio signalcomprises computing a phase value of the audio signal that isrepresentative of a phase of the first sound at the microphone relativeto a phase of the first sound at the position of the noise source,wherein the complementary signal is based upon the phase of the firstsound at the microphone.
 3. The vehicle of claim 1, the acts furthercomprising recovering an original noise waveform representative of thefirst sound as emitted by the noise source by backpropagating the audiosignal from a location of the microphone to the position of the noisesource based upon a noise propagation model, wherein computing thecomplementary signal is based upon the original noise waveform.
 4. Thevehicle of claim 3, the acts further comprising generating an expectednoise signal by forward propagating the original noise waveform from theposition of the noise source to a location in the interior of thevehicle based upon the noise propagation model, wherein computing thecomplementary signal is based upon the expected noise signal.
 5. Thevehicle of claim 1, wherein computing the complementary signal is basedupon a noise propagation model, the noise propagation model based uponat least one of an altitude of the vehicle, a temperature of the drivingenvironment, or a humidity of the driving environment.
 6. The vehicle ofclaim 1, wherein the sensor system comprises a lidar sensor, whereinidentifying the position of the noise source comprises identifying athree-dimensional position of the noise source based upon output of thelidar sensor.
 7. The vehicle of claim 1, wherein the sensor systemcomprises a radar sensor, wherein identifying the position of the noisesource comprises identifying a range to the noise source based uponoutput of the radar sensor.
 8. The vehicle of claim 1, wherein themicrophone is a first microphone, wherein the sensor system comprises amicrophone array that includes the first microphone and a secondmicrophone, the first sound impinges on the second microphone andwherein further identifying the position of the noise source comprisesidentifying a range to the noise source based upon time distance ofarrival (TDOA).
 9. A method for active-noise-cancellation in an interiorof a vehicle, the method comprising: receiving an audio signal from amicrophone, the audio signal indicative of a first sound that is emittedby a noise source and that is incident on the microphone; determining aposition of the noise source in a driving environment of the vehiclebased upon a sensor signal received from a sensor system mounted on thevehicle, the sensor signal indicative of objects in the drivingenvironment; computing a complementary signal based upon the position ofthe noise source and the audio signal received from the microphone; andoutputting the complementary signal to the speaker, wherein thecomplementary signal is configured to cause the speaker to emit a secondsound that interferes with the first sound in the interior of thevehicle, thereby attenuating the first sound.
 10. The method of claim 9,wherein determining the location of the noise source comprises:identifying a plurality of objects in the driving environment of thevehicle based upon data output by the sensor system; determining thatthe noise source is a first object in the plurality of objects; andcomputing the position of the first object based upon the sensor signalreceived from the sensor system.
 11. The method of claim 10, whereindetermining that the noise source is the first object in the pluralityof objects comprises: identifying an amplitude of a spectral componentof the audio signal; and determining that the noise source is the firstobject based upon the amplitude of the spectral component and a type ofthe first object.
 12. The method of claim 11, wherein determining thatthe noise source is the first object based upon the amplitude of thespectral component and the type of the first object comprises comparingthe amplitude of the spectral component to a signature corresponding tothe type of the first object.
 13. The method of claim 9, whereincomputing the complementary signal comprises: computing a noise waveformbased upon the audio signal and a propagation model that isrepresentative of propagation of sounds through the driving environmentof the vehicle, the noise waveform representative of the first sound asemitted from the noise source at the position of the noise source; andcomputing the complementary signal based upon the noise waveform. 14.The method of claim 13, wherein computing the complementary signal basedupon the noise waveform comprises: modeling propagation of the noisewaveform from the position of the noise source to a position of thevehicle based upon the propagation model to generate a propagated noisewaveform; and computing the complementary signal based upon thepropagated noise waveform.
 15. A vehicle comprising: a speakerpositioned in a passenger cabin of the vehicle; a microphone, whereinthe microphone outputs an audio signal that is indicative of noiseemitted by a noise source in a driving environment of the vehicle; asensor that outputs data indicative of positions of objects in thedriving environment of the vehicle; and a computing system configured toperform the following acts: determining a position of the noise sourcein the driving environment of the vehicle based upon output of thesensor; computing a complementary signal based upon the position of thenoise source and the audio signal; and outputting the complementarysignal to the speaker, wherein the complementary signal is configured tocause the speaker to emit a sound that causes the noise to be attenuatedin the passenger cabin of the vehicle.
 16. The vehicle of claim 15,wherein computing the complementary signal is further based upon apropagation model that models propagation of the noise from the positionof the noise source to a position of the vehicle.
 17. The vehicle ofclaim 16, wherein the propagation model includes a transfer functionthat represents modification of the noise from an exterior of thevehicle to the passenger cabin of the vehicle, wherein computing thecomplementary signal comprises applying the transfer function to a noisewaveform that is representative of the noise when the noise is incidentat the exterior of the vehicle.
 18. The vehicle of claim 15, wherein thesensor is a lidar sensor, and wherein determining the position of thenoise source comprises identifying a point in space that isrepresentative of the position of the noise source based upon output ofthe lidar sensor.
 19. The vehicle of claim 15, wherein computing thecomplementary signal is based further upon a position of the speaker inthe passenger cabin of the vehicle, the vehicle further comprising asecond speaker, the acts further comprising: computing a secondcomplementary signal based upon the position of the noise source, theaudio signal, and a position of the second speaker in the passengercabin of the vehicle; and outputting the second complementary signal tothe second speaker, wherein the second complementary signal isconfigured to cause the second speaker to emit a second sound thatcauses the noise to be further attenuated in the passenger cabin of thevehicle.
 20. The vehicle of claim 15, wherein determining the positionof the noise source in the driving environment comprises: determining acoarse position solution, the coarse position solution indicative of adirection from which the noise was received at the vehicle; anddetermining the position of the noise source based upon the coarseposition solution and the output of the sensor, wherein the position ofthe noise source is more precise than the coarse position solution.